Apparatus and method for processing 3D images through adjustment of depth and viewing angle

ABSTRACT

An apparatus for processing a three-dimensional (3D) image is provided. The apparatus includes a motion estimation module and a motion interpolation module. The motion estimation module estimates a motion vector between a first object in a first-eye image and a second object in a second-eye image. The first object is the same as or similar to the second object. The motion interpolation module multiplies the motion vector by a first shift ratio to generate a first motion vector. The motion interpolation module generates a shifted first object by interpolation according to the first motion vector and the first object.

This application claims the benefit of Taiwan application Serial No.101101839, filed Jan. 17, 2012, the subject matter of which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates in general to a three-dimensional (3D) imageprocessing technique, and more particularly, to a technique foradjusting a distance and a viewing angle relative to a 3D image and anobserver of the 3D image.

2. Description of the Related Art

With advancements in related software and hardware techniques,commercial and household 3D display equipment has gradually matured, and3D image techniques have also drawn much attention in the multimediafield. Current 3D display techniques are in general divided into anactive type and a passive type.

An active 3D image display technique refers to alternately presentingleft-eye and right-eye images on a monitor. Dedicated glasses worn by aviewer shield the right eye of the viewer when a left-eye image ispresented and shield the left eye of the viewer when a right-eye imageis presented. The visual system of the viewer automatically combines theleft-eye image and the right eye image to form a 3D image. Due to visionpersistence, the brief shieldings by the 3D glasses against thepresented images remain unnoticed to the viewer as long as a switchingfrequency of the left-eye and right-eye images is fast enough.

A passive 3D image display technique refers to simultaneously presentingleft-eye and right-eye images in a same image frame. Referring to FIG.1, odd-row pixels R1, R2, R3 . . . correspond to the right-eye image,and even-row pixels L1, L2, L3 . . . correspond to the left-eye image,with the two being horizontally staggered. A passive 3D image displaycomprises an exteriorly adhered polarizing film. For example, apolarization angle corresponding to the odd-row pixels R1, R2, R3 . . .may be designed as 45 degrees, and polarization angle corresponding tothe even-row pixels L1, L2, L3 may be designed as 135 degrees. Thus, theleft lens and the right lens of the glasses worn by the viewerrespectively allow the passing of light beams with a polarization angleof 45 degrees and 135 degrees, so that different images can be receivedby the left and right eyes, respectively. Similarly, the viewerautomatically combines the left-eye image and the right eye imagereceived at the same time through human visual characteristics to form acorresponding 3D image.

For both of the active and passive 3D image display techniques, thecompleted left-eye images and right-images can only be modified oradjusted with complex and expensive devices. However, a trend to providea user with user-independent options and flexibilities for adjustingimage content emerges, such as allowing a user to manually adjustbrightness, contrast and depth of 3D images.

SUMMARY OF THE INVENTION

The invention is directed to an apparatus and method for processing a 3Dimage to fulfill the need for adjusting a depth and a viewing angle ofthe 3D image. In the apparatus and method for processing a 3D image ofthe invention, the depth and viewing angle of the 3D image can beadjusted through motion estimation and motion interpolation withoutimplementing a dedicated and complex 3D image device.

According to one embodiment the present invention, a 3D image processingapparatus is provided. The apparatus includes a motion estimation moduleand a motion interpolation module. The motion estimation moduleestimates a motion vector between a first object in a first-eye imageand a second object in a second-eye image. The first object is the sameas or similar to the second object. The motion interpolation modulemultiplies the motion vector by a first shift ratio to generate a firstmotion vector, and generates a shifted first object by interpolationaccording to the first motion vector and the first object.

In an alternative embodiment of the present invention, the motioninterpolation module further multiplies the motion vector by a secondshift ratio to generate a second motion vector, and generates a shiftedsecond object according to the second motion vector and the secondobject.

According to another embodiment the present invention, a 3D image systemis provided. In addition to the above motion estimation module andmotion interpolation module, the 3D image system further includes aplayback module for simultaneously or alternately playing modifiedleft-eye and right-eye images.

According to yet another embodiment the present invention, a 3D imageprocessing method is provided. The method includes steps of: estimatinga motion vector between a first object in a first-eye image and a secondobject in a second-eye image, the first object being the same or similarto the second object; multiplying the motion vector by a first shiftratio to generate a first motion vector; and generating a shifted firstobject according to the first motion vector and the first object.

The above and other aspects of the invention will become betterunderstood with regard to the following detailed description of thepreferred but non-limiting embodiments. The following description ismade with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an example of a three-dimensional (3D) image.

FIG. 2 is a block diagram of a 3D image processing apparatus accordingto one embodiment of the present invention.

FIG. 3 is an example of a left-eye image and a corresponding right-eyeimage.

FIGS. 4A to 4E are examples of forming an image according to differentshift ratios.

FIG. 5A is a schematic diagram of a motion vector between two objects;FIGS. 5B and 5C are a shifted left-eye object and a shifted right-eyeobject.

FIGS. 6A and 6B are schematic diagram of simultaneously generatingdifferent types of shifted objects.

FIGS. 7A and 7B are schematic diagrams illustrating a stereotypic effectof an MEMC apparatus.

FIG. 8 is a flowchart of a 3D image processing method according to oneembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 2 shows a three-dimensional (3D) image processing apparatus 200according to one embodiment of the present invention. The 3D imageprocessing apparatus 200 includes a motion estimation module 22, amotion interpolation module 24 and a playback module 26. In practice,the 3D image processing apparatus 200 may be integrated in a systemfeaturing a 3D image playback function, such as a television, a DVDplayer or a computer. It should be noted that the playback module 26 isan optional component of the 3D image processing apparatus 200.

FIG. 3 shows an example of a left-eye image and a correspondingright-eye image. In this example, an object X in the left-eye image andan object Y in the right-eye image correspond to a same potted plant.The object X and the object Y may be identical, or may be similar butslightly different. After simultaneously or sequentially (alternately)viewing the left-eye and right-eye images, the viewer combines theobject X and the object Y into a 3D image of the potted plant. FIG. 3also depicts that a position of the object X in the left-eye imagediffers from a position of the object Y in the right-eye image. Morespecifically, the object X is presented at the left half of the screen,whereas the object Y is presented at the right half of the screen.Referring to FIG. 4A, a combined image IMG perceived by the viewer isformed behind the screen, and a depth of the combined image IMGperceived by the viewer is D.

Referring to FIG. 4B, if the object X in the left-eye image is replacedby an object X′ while the object Y in the right-eye image remainsunchanged, a combined image perceived by the viewer becomes IMG′.Compared to the image IMG, the viewer feels that the image IMG′ islocated more to the right and has a smaller depth (i.e., the IMG′appears to be closer and zoomed in to the viewer). Referring to FIG. 4C,if the object Y in the right-eye image is replaced by an object Y′ whilethe object X in the left-eye image remains unchanged, a combined imageIMG′ perceived by the viewer is closer to the left, and appears closerand zoomed in compared to the image IMG. Referring to FIG. 4D, if theobject X in the left-eye image is replaced by the object X′ while theobject Y in the right-eye image is also replaced by the object Y′, andthe displacement from the object X to the object X′ is identical to thedisplacement from the object Y′ to the object Y, the combined image IMG′perceived by the viewer appears to be at a same horizontal position butcloser and zoomed in compared to the image IMG. Referring to FIG. 4E,the combined image IMG generated by the object X and the object Y maypossibly form in the front of the screen. If the object X in theleft-eye image is replaced by the object X′ while the object Y in theright-eye image is replaced by the object Y′, and the displacement fromthe object X to the object X′ is identical to the displacement from theobject Y′ to the object Y, the combined image IMG′ perceived by theviewer appears to be at a same horizontal position but farther andzoomed out compared to the image IMG.

It is clear from the above examples that the 3D image depth andleft/right positions of the object X and/or the object Y can be adjustedby changing the positions of the object X and/or the object Y. Thus, inthe 3D image processing apparatus 200 according to one embodiment of thepresent invention, by changing positions of objects in the left-eyeimage and/or the right-eye image through motion estimation and motioninterpolation, the depth and/or left and right positions of one or moreobjects in a 3D image can be adjusted.

The motion estimation module 22 estimates a motion vector between afirst object in a first-eye image and a second object in a second-eyeimage. The first object is the same as or similar to the second object.Taking FIG. 3 as an example, the motion estimation module 22 determinesa coordinate of a center of the object X in the left-eye image and acoordinate of a center of the object Y in the right-eye image, andcalculates a displacement of the two coordinates as a motion vector MVbetween the object X and the object Y. An example of taking thefirst-eye image as a left-eye image and the second-eye image as acorresponding right-eye image shall be described. The left-eye imageincludes a left-eye object X, and the right-eye image includes aright-eye object Y. Image content of the objects X and Y may beidentical or similar but different.

Assume the motion vector MV between left-eye object X and the right-eyeimage Y is already identified by the motion estimation module 22, asshown in FIG. 5A. The motion interpolation module 24 first multipliesthe motion vector MV by a first shift ratio a1 to generate a firstmotion vector MV*a1. Referring to FIG. 5B, the motion interpolationmodule 24 generates a shifted left-eye image including a shiftedleft-eye object X′, by interpolation according to the first motionvector MV*a1 and the left-eye image including the left-eye object X.Similarly, referring to FIG. 5C, the motion interpolation module 24 alsomultiplies the motion vector MV by a second shift ratio a2 to generate asecond motion vector MV*a2. According to the second motion vector MV*a2and the right-eye image including the right-eye object Y, the motioninterpolation module 24 generates a shifted right-eye image including ashifted right-eye object Y′ by interpolation.

In practice, an object generated by interpolation may be the same as ordifferent from an original object. In one embodiment, the shiftedleft-eye object X′ and the left-eye object X are identical. In anotherembodiment, the motion interpolation module 24 generates the shiftedleft-eye object X′ according to the left-eye object X by aninterpolation algorithm, and generates the shifted right-eye object Y′according to the right-eye object Y also by the interpolation algorithm.In yet another embodiment, the motion interpolation module 24 generatesthe shifted left-eye object X′ and the shifted right-eye object Y′according to the left-eye object X and the right-eye object Y by anotherinterpolation algorithm.

The first shift ratio a1 and the second shift ratio a2 are not limitedto specific values. In addition, the first shift ratio a1 and the secondshift ratio a2 may be the same or different.

An example of the motion vector MV depicted in FIG. 5A shall be given.In response to a request for moving a combined image corresponding tothe objects X and Y to the right and zooming in the image (e.g., asshown in FIG. 4B), the motion interpolation module 24 sets the firstshift ratio a1 as a positive number. Thus, the first motion vector MV*a1generated is in a same direction as the motion vector MV, so that theshifted left-eye object X′ is relatively at the right of the left-eyeobject X. Meanwhile, the motion interpolation module 26 may set thesecond shift ratio a2 to zero, so that the shifted right-eye object Y′remains at the same position of the right-eye object Y. Alternatively,the procedure for generating the shifted right-eye object Y′ is notperformed at all. It should be noted that, the remaining part except theobject X of the left-eye image and the remaining part except the objectY of the right-eye image may substantially stay unchanged, or may beapplied by corresponding changes resulted from shifting the objects Xand Y.

In response to a request for moving a combined image corresponding tothe objects X and Y to the left and zooming in the image (e.g., as shownin FIG. 4C), the motion interpolation module 24 sets the first shiftratio a1 to zero and sets the second shift ratio a2 as a negativenumber. Thus, the second motion vector MV*a2 generated is in an oppositedirection from the motion vector MV, so that the shifted right-eyeobject Y′ is relatively at the left of the right-eye object Y.

Further, in response to a request for zooming in a combined imagecorresponding to the objects X and Y but keeping the horizontal positionunchanged (e.g., as shown in FIG. 4D), the motion interpolation module24 sets the first shift ratio a1 as a positive number and sets thesecond shift ratio a2 as a negative number, with an absolute value ofthe first shift ratio al being equal to an absolute value the secondshift ratio a2. Thus, the first motion vector MV*a1 generated is in anopposite direction from the second motion vector MV*a2 generated, sothat the shifted left-eye object X′ is relatively at the right of theleft-eye object X and the shifted right-eye object Y′ is relatively atthe left of the right-eye object Y.

Further, in response to a request for zooming out a combined imagecorresponding to the objects X and Y but keeping the horizontal positionunchanged (e.g., as shown in FIG. 4E), the motion interpolation module24 sets the first shift ratio a1 as a negative number and sets thesecond shift ratio a2 as a positive number, with an absolute value ofthe first shift ratio a1 being equal to an absolute value the secondshift ratio a2. Thus, the first motion vector MV*a1 generated is in anopposite direction from the second motion vector MV*a2 generated, sothat the shifted left-eye object X′ is relatively at the left of theleft-eye object X and the shifted right-eye object Y′ is relatively atthe right of the right-eye object Y.

In one embodiment, referring to FIG. 6A, according to the first motionvector MV*a1 and a left-eye image including a left-eye object X, themotion interpolation module 24 is designed to simultaneously generate aleft-shifted left-eye image including a left-shifted left-eye object X1and a right-shifted left-eye image including a right-shifted left-eyeobject X2 by interpolation. Referring to FIG. 6B, according to thesecond motion vector MV*a2 and a right-eye image including a right-eyeobject Y, the motion interpolation module 24 further simultaneouslygenerates a left-shifted right-eye image including a left-shiftedright-eye object Y1 and a right-shifted right-eye image including aright-shifted right-eye object Y2. Subsequently, according to a requestof a user or from an upper-tier request, from the left-eye image(including the left-eye object X), the left-shifted left-eye image(including the left-shifted left-eye object X1) and the right-shiftedleft-eye image (including the right-shifted left-eye object X2), themotion interpolation module 24 selects one image as the shifted left-eyeimage including the shifted left-eye object X′. Similarly, from theright-eye image (including the right-eye object Y), the left-shiftedright-eye image (including the left-shifted right-eye object Y1) and theright-shifted right-eye image (including the right-shifted right-eyeobject Y2), the motion interpolation module 24 selects one as theshifted right-eye image including the shifted right-eye object Y′. Forexample, in response to a request for zooming in a combined imagecorresponding to the objects Y and Y but keeping the horizontal positionunchanged, the motion interpolation module 24 may select theright-shifted left-eye image (including the right-shifted left-eyeobject X2) and the left-shifted right-eye image (including theleft-shifted right-eye object Y1).

It should be noted that, the shifted left-eye objects X1 and X2 may bedifferent from the left-eye object X. For example, the motioninterpolation module 24 may interpolate each pixel in the left-eyeobject X according to the motion vector MV to generate the shiftedleft-eye objects X1 and X2. Similarly, the shifted right-eye objects Y1and Y2 may be different from the right-eye object Y. For example, themotion interpolation module 24 may interpolate each pixel in theright-eye object Y according to the motion vector MV to generate theshifted right-eye objects Y1 and Y2.

In practice, the motion estimation module 22 and the motioninterpolation module 24 may be included in a same motion estimation andmotion compensation (MEMO) apparatus. Conventionally, the MEMO apparatusis utilized for processing two-dimensional (2D) images. FIGS. 7A and 7Bshow schematic diagrams of stereotypic usage of an MEMO apparatus.Referring to FIG. 7A, the MEMO apparatus first identifies a motionvector between two original frames (frame A and frame B). In thisexample, the motion interpolation performed by the MEMO apparatusinterpolates a new frame between the frames A and B according to themotion vector MV and the frames A and B. Content of the new frame is anaverage of contents of frames A′ and B′ in FIG. 7B. The MEMO apparatusis capable of generating the frames A′ and B′ according to the motionvector MV. As shown in FIG. 7B, a relative motion vector between theframe A′ and the original frame A is the motion vector MV multiplied bya shift ratio r, and a relative motion vector between the frame B′ andthe original frame B is an opposite vector (i.e., −MV) of the motionvector MV multiplied by another shift ratio (1-r).

The shift ratio r may be regarded as the foregoing first shift ratio a1,and the shift ratio (1-r) added with a negative sign may be regarded asthe foregoing second shift ratio a2. In other words, in this embodiment,a sum of the first shift ratio a1 and the negative second shift ratio a2is 1. If the left-eye object X is selected as the original frame A andthe right-eye object Y is selected as the original frame B, the shiftedleft-eye object X′ is relatively at the right of the left-eye object X,and the shifted right-eye object Y′ is relatively at the left of theright-eye object Y. For example, for a shift ratio of 0.5, thehorizontal positions of the new objects X′ and Y′ are right in themiddle of the objects X and Y in the new frame generated byinterpolation to be equidistant from the objects X and Y. In anothercase, if the left-eye object X is selected as the original frame B andthe right-eye object Y is selected as the original frame A, the shiftedleft-eye object X′ is relatively at the left of the left-eye object, andthe shifted right-eye object Y′ is relatively at the right of theright-eye object Y.

As described, the 3D image processing apparatus 200 according to oneembodiment of the present invention adjusts the depth as well as leftand right positions of a 3D image through motion estimation and motioninterpolation. The motion interpolation module 24 selects differentcombinations of the shift ratios a1 and a2 to generate different imageformation. The shift ratios may be user-adjusted within a predeterminedrange by a system designer according to hardware specifications.Moreover, the motion interpolation module 24 may also solely shifteither the left-eye object X or the right-eye object Y instead ofsimultaneously generating the shifted left-eye image and the shiftedright-eye image.

It should be noted that, when a position of a newly combined image IMG′is not located on a central axis of the line of sight of the viewer asthe original image IMG, a visual effect is equivalent to a situationwhere the viewer moves to the right or to the left of the originalposition. That is to say, the 3D image processing apparatus 200 is alsocapable of changing a viewing angle.

Again referring to FIG. 2, the left-eye image and right-eye imageselectively modified by the motion interpolation module 24 are providedto the playback module 26. The modified left-eye image includes theshifted left-eye object X′, and the modified right-eye image includesthe shifted right-eye object Y′. For an active 3D image, the playbackmodule 26 alternately plays the modified left-eye image and right-eyeimage. For a passive 3D image, the playback module 26 simultaneouslyplays the modified left-eye image and the modified right-eye image in astaggered manner, as shown in FIG. 1.

FIG. 8 shows a flowchart of a 3D image processing method according toanother embodiment of the present invention. Referring to FIG. 8, inStep S81, a motion vector between a first object in a first-eye imageand a second object in a second-eye image is estimated. The first objectis the same as or similar to the second object. In Step S82, the motionvector is multiplied by a first shift ratio to generate a first motionvector. In Step S83, according to the first motion vector and thefirst-eye image, a modified first-eye image is generated byinterpolation. In Step S84, the motion vector is multiplied by a secondshift ratio to generate a second motion vector. In Step S85, accordingto the second motion vector and the second-eye image, a modifiedsecond-eye image is generated by interpolation. In Step S86, themodified first-eye image and the modified second-eye image aresimultaneously or alternately played.

It should be noted that, in a situation where only an object at one sideneeds to be adjusted, Steps S84 and S85 may be omitted. Further, StepS86 is optional in the flow. Operation details and results of the stepsmay be referred in associated descriptions on the foregoing 3D imageprocessing apparatus 200, and shall be omitted herein.

Therefore, to satisfy the need for adjusting the 3D image depth, a novel3D image processing apparatus and 3D image process method is provided asin the description of the embodiments. In the 3D image processingapparatus and method of the present invention, the depth and viewingangle of the 3D image can be adjusted through motion estimation andmotion interpolation without implementing a dedicated and complex 3Dimage device.

It is noted that the motion estimation module and motion interpolationmodule may be implemented in hardware, software or a combination ofhardware and software. For example, an Application Specific IntegratedCircuit (ASIC) may be provided that is configured to operate inaccordance with the functionality described herein. Likewise, logicinstructions stored in a memory (not shown) may be provided which, whenexecuted by processor, cause the processing apparatus 200 to operate inaccordance with the functionality described herein.

While the invention has been described by way of example and in terms ofthe preferred embodiments, it is to be understood that the invention isnot limited thereto. On the contrary, it is intended to cover variousmodifications and similar arrangements and procedures, and the scope ofthe appended claims therefore should be accorded the broadestinterpretation so as to encompass all such modifications and similararrangements and procedures.

What is claimed is:
 1. A three-dimensional (3D) image processingapparatus, comprising: a motion estimation module that estimates amotion vector between a first object in a first-eye image and a secondobject in a second-eye image, the first object being at least similar tothe second object; and a motion interpolation module that multiplies themotion vector by a first shift ratio, for moving the first object in thefirst-eye image, to generate a first motion vector, and generating amodified first-eye image by interpolation according to the first motionvector and the first-eye image and further multiplies the motion vectorby a second shift ratio to generate a second motion vector, andgenerates a modified second-eye image by interpolating according to thesecond motion vector and the second-eye image, wherein a sum of thefirst shift ratio and the second shift ratio is 1, wherein the first-eyeimage is one of a right-eye image and a corresponding left-eye image,and the second-eye image is the other of the right-eye image and thecorresponding left-eye image, wherein, when viewed, the first-eye imageand the second-eye image are combined into a 3D image, and wherein themodified first-eye image is one of another right-eye image and anothercorresponding left-eye image which, when viewed, are combined intoanother 3D image.
 2. The apparatus according to claim 1, wherein themodified first-eye image comprises a shifted first object correspondingto the first object, the modified second-eye image comprises a shiftedsecond object corresponding to the second object, the first-eye image isa left-eye image, and the second-eye image is a right-eye image; inresponse to a zoom-in request, the motion interpolation module sets thefirst shift ratio to locate the shifted first object at the right of thefirst object, and sets the second shift ratio to locate the shiftedsecond object at the left of the second object; in response to azoom-out request, the motion interpolation module sets the first shiftratio to locate the first shifted object at the left of the firstobject, and sets the second shift ratio to locate the second shiftedobject at the right of the second object.
 3. The apparatus according toclaim 1, wherein the motion interpolation module generates aleft-shifted first-eye image comprising a left-shifted first object anda right-shifted first-eye image comprising a right-shifted first objectby interpolation according to the first motion vector and the first-eyeimage, generates a left-shifted second-eye image comprising aleft-shifted second object and a right-shifted second-eye imagecomprising a right-shifted second object by interpolating the secondmotion vector and the second-eye image, selects one of the first-eyeimage, the left-shifted first-eye image and the right-shifted first-eyeimage as the modified first-eye image, and selects one of the second-eyeimage, the left-shifted second-eye image and the right-shiftedsecond-eye image as the modified second-eye image; wherein, theleft-shifted first object and the right-shifted first object correspondto the first object, and the left-shifted second object and theright-shifted second object correspond to the second object.
 4. Theapparatus according to claim 1, further comprising: a playback module,for simultaneously or alternately displaying the modified first-eyeimage and the modified second-eye image; wherein, the modified first-eyeimage comprises a shifted first object corresponding to the firstobject, and the modified second-eye image comprises a shifted secondobject corresponding to the second object.
 5. A three-dimensional (3D)image processing method, comprising: estimating a motion vector betweena first object in a first-eye image and a second object in a second-eyeimage, the first object being at least similar to the second object;multiplying the motion vector by a first shift ratio, for moving thefirst object in the first-eye image, to generate a first motion vector;generating a modified first-eye image by interpolation according to thefirst motion vector and the first-eye image; multiplying the motionvector by a second shift ratio to generate a second motion vector; andgenerating a modified second-eye image by interpolating according to thesecond motion vector and the second-eye image, wherein a sum of thefirst shift ratio and the second shift ratio is 1; and displaying themodified first-eye image and the modified second-eye image on a display,wherein the first-eye image is one of a right-eye image and acorresponding left-eye image, and the second-eye image is the other ofthe right-eye image and the corresponding left-eye image, wherein, whenviewed, the first-eye image and the second-eye image are combined into a3D image, and wherein the modified first-eye image is one of anotherright-eye image and another corresponding left-eye image which, whenviewed, are combined into another 3D image.
 6. The method according toclaim 5, wherein the modified first-eye image comprises a shifted firstobject corresponding to the first object, the modified second-eye imagecomprises a shifted second object corresponding to the second object,the first-eye image is a left-eye image, and the second-eye image is aright-eye image; in response to a zoom-in request, the first shift ratiois set to locate the shifted first object at the right of the firstobject, and the second shift ratio is set to locate the shifted secondobject at the left of the second object; in response to a zoom-outrequest, the first shift ratio is set to locate the first shifted objectat the left of the first object, and the second shift ratio is set tolocate the second shifted object at the right of the second object. 7.The method according to claim 5, wherein the step of generating themodified first-eye image comprises generating a left-shifted first-eyeimage comprising a left-shifted first object and a right-shiftedfirst-eye image comprising a right-shifted first object by interpolationaccording to the to the first motion vector and the first-eye image, andselecting one of the first-eye image, the left-shifted first-eye imageand the right-shifted first-eye image as the modified first-eye image;and the step of generating the modified second-eye image comprisesgenerating a left-shifted second-eye image comprising a left-shiftedsecond object and a right-shifted second-eye image comprising aright-shifted second object by interpolating the second motion vectorand the second-eye image, and selecting one of the second-eye image, theleft-shifted second-eye image and the right-shifted second-eye image asthe modified second-eye image.
 8. The method according to claim 5,further comprising: simultaneously or alternately displaying themodified first-eye image and the modified second-eye image; wherein, themodified first-eye image comprises a shifted first object correspondingto the first object, and the modified second-eye image comprises ashifted second object corresponding to the second object.